1. Technical Field
The present invention relates to a biological sample reaction chip and to a biological sample reaction method for carrying out biological sample reactions such as nucleic acid amplification.
2. Related Art
Growing attention is being focused on methods for carrying out, for instance, chemical analysis, chemical synthesis or bio-related analysis using microfluidic chips in which microchannels are provided in a glass plate or the like. Microfluidic chips, which are also called micro-Total Analytical Systems (micro-TAS), Lab-on-a-chip and the like, are advantageous in that they require smaller amounts of specimens and reagents, have shorter reaction times and generate fewer waste products than existing devices. Thus, microfluidic chips are thus a promising application in a wide range of fields such as medical diagnosis, environmental and foodstuff onsite analysis, and in the manufacture of pharmaceuticals and chemicals, where test costs can be reduced since reaction amounts may be small. Likewise, testing can be made more efficient by considerably shortening also reaction times, since samples and reagents are used in small amounts. When used in medical diagnosis, in particular, microfluidic chips are advantageous in that they can use less of a specimen, for instance a blood sample, which allows easing the burden placed on the patient.
Known methods for amplifying genes such as DNA and RNA, used as samples, include polymerase chain reaction (PCR). In PCR, a mixture of target DNA and reagents is placed in a tube where the reagents and the target DNA are made to react, by repeating a so-called thermal cycle that involves changes of temperature in three stages, for instance, 55° C., 72° C. and 94° C., over several minutes, using a temperature control device. In each temperature cycle the target DNA can be amplified, to roughly a double amount, through the action of an enzyme called polymerase.
So-called real-time PCR, using special fluorescent probes, has come into use in recent years. In real-time PCR, DNA can be quantified while the amplification reaction is taking place. Real-time PCR boasts high measurement sensitivity and reliability, and is hence widely used in research and clinical testing.
Conventional devices, however, were problematic in that the amount of reaction liquid required for PCR is normally of several tens of μl, while basically only one gene could be determined in one reaction system. Some methods allow measuring simultaneously about four genes by introducing plural fluorescent probes and discriminating between respective colors, but determining simultaneously more than four genes inevitably calls for an increase in the number of reaction systems. The amount of DNA extracted from the specimen is normally small, and reagents are expensive. It has been thus difficult to determine simultaneously multiple reaction systems.
JP-A-2006-126010 and JP-A-2006-126011 disclose inventions in which liquid analyte samples such as a PCR reaction solution or blood are accurately introduced into a plurality of chambers, using a rotationally driven device.
JP-A-2000-236876 discloses a method that involves preparing micro-wells integrated on a semiconductor substrate, and carrying out PCR in the wells, to amplify and analyze collectively multiple DNA samples, using small sample amounts.